Refrigerating apparatus



April 16, 1940- D. L. KAUFMAN 2,197,582

REFRIGERATING APPARATUS Filed March 26, 1958 /20 f2.2 A24l ggz 54?@ QINVE 0R.

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W Apr.. 16, 1940 UNITED STATES PATENT OFFICE BEFBIGERATING APPARATUSApplication March 26, 1938, Serial No. 198,290

3 Claims.

thermostat bulb has been used, the thermostatv bulb has ordinarily beenclamped to the outside oi the evaporator or to the outside of the returnconduit, adjacent the outlet of the evaporator. Such a form ofconnection does not provide a very rapid heat transfer between thecontents of the evaporator or the contents of the return conduit andconsequently with such an arrangement the control is not very sensitive.

It has also been proposed to place the thermostat bulb directly in thereturn conduit but such a scheme eliminates one of the chief advantagesci the thermostat bulb type of control system, namely, that the controlmay be removed from tlg? system without opening the refrigerant circ t.

it is an object of my invention to provide an improved means which willprovide much more rapid heat transfer between the contents of the returnconduit or evaporating means and the thermostat bulb, without making itnecessary to open up the refrigerant system to remove the thermostatbulb from the system.

It is another object of my invention to provide a form of well providedin the refrigerating system at the particular point where it is desiredto take the temperature.

It is still another object of my invention to provide an improved wellconstruction for thermostat bulbs and thermometers in the refrigeratingsystemA and other types oi systems requiring different forms oftemperature measurement.

It is a further object of my invention to provide means for improvingthe heat transfer between the wall of the Well and the thermostat bulb.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing, wherein a preferred form of the present invention is clearlyshown.

In the drawing:

Fig. l is a diagrammatic representation of a refrigerating systemembodying my invention;

Fig. 2 is a diagrammatic representation of another iorm ,ofrefrigerating system embodying my invention; and

Fig. 3 is an enlarged sectional view of the well and fitting used inFigs. 1 and 2.

Bjriey, l have shown two refrigerating systems of the direct exnsiontype provided with T- shaped fittings at the outlet of the evaporatingmeans. Each of these T-shaped fittings has one of the aligned legsconnected to the outlet of the evaporating means, while the otheraligned leg is closed by a cap containing a copper well extendingthrough the aligned legs of the fitting into the outlet of theevaporating means. These wells each contain a thermostat bulb heldpressed against the sidewall of the well by a-thin spring brass stripwhich is slightly longer than the thermostat bulb. The well is closedby'a split rubber stopper which encircles the small tube connected tothe thermostat bulb and fits within the mouth of thelwell.

Referring now to the drawing and more particularly to Fig. l, there isshown a refrigerant liquefying means including a compressor 20 driven byan electric motor 22 for compressing refrigerant and forwarding thecompressed refrigerant 1to a condenser 24 where the compressedrefrigerant is liqueed and drains into the receiver 26. From thereceiver 26 liquid refrigerant is forwarded to the.` supply conduit 2Bto a thermostatic automatic expansion valve 30 which controls the flowof liquid refrigerant into the evaporating means 32. The outlet of theevaporating means 32 is provided with a, T-shaped fitting 34 having oneof its aligned legs connected to the outlet of the evaporating means andhaving another of the legs connected to the return conduit 36 whichconnects to the inlet of the compressor.l The operation of thecompressor 2li and its driving motor 22 is controlled by a snap actingswitch means 38 controlled by thermostat bulb l0 located adjacent or incontact with the evaporating means 32 for controlling the operation ofthe liquefying means in accordance with the temperature of theevaporating means 32.

The expansion valve has a diaphragm means responsive to the pressure ofthe refrigerant within the evaporating means 32 and also has athermostatic portion connected by a tube 42 to a thermostat'bulb.Heretofore such a thermostat bulb has ordinarily been clamped by someform of clamping means to the outlet of the evaporating means. Such'aclamping arrangement did not provide good heat transfer between thegases in the outlet and the thermostat bulb and for that reason thisarrangement was not very sensitive.

In order to improve the sensitivity of the control of refrigerantflowing into the evaporating means 30 I have provided an assembly whichincludes relatively long thermostat well M and a cap member 4t providedwith the aperture receiving the anged mouth of the Well. This receiverflanged mouth of the well is silver soldered to the portion of the capmember immediately surrounding the mouth of the well. The cap member 46is preferably made of heavy copper while the well M is made of thinnercopper. Each of these pieces may be made from seamless copper tubing andsoldered together by the use of.' silver solder. The closed end of thewell 44 may be made by spinning and silver soldering in order to sealthe inner end of the well 44. This assembly of the cap and the well isinserted in one of the aligned legs of the fitting 34, as shown in Fig.3, and sweat-soldered in place.

The well not only extends through the fitting but also extends aconsiderable distance into the outlet of the evaporating means 32. Thethermostat bulb 48 is connected to the end of the tube 42and is insertedinto the well after a thin at strip 50 of phosphor bronze has beenpreviously inserted into the well. This thin fiat strip 50 of springbronze holds the bulb 48 tightly against one portion of the wall of thewell 44. The mouth of the well 44 is closed by a pierced split rubberstopper 52 which receives the tube 44 and is inserted into the mouth ofthe well. Preferably the well contains only air or some other gaseousfluid, so that the specific heat of the well and the thermostat bulb iskept as low as possible. However, ii it is desired to make thisarrangement less sensitive or if it is desired to secure better heattransfer the well may be filled with some suitable heat transfer liquidwhich may have either a low or a high specific heat, as desired.

The well may be made any length desired in order to position the bulbproperly. The bulb may be moved longitudinally within the well to adjustthe position of the bulb tothe exact point desired in order to obtainthe best control. y Preferably the assembly of the cap member and wellis sweat-soldered to the T tting when tleT fitting is soldered into therefrigerant circuit.

In Fig. 2 there is shown a very similar refrigerating system including acompressor |20 driven by an electric motor |22, a condenser |24 and a|26. Supply and return conduits |28 and |36 connect the liquefying meanswith the evaporating means |32. An automatic expansion valve |30 or arestrictor is used to control the iiow of liquid refrigerant into theevaporating means |32. A T-shaped fittingA |34 connects the outlet ofthe evaporating means with the return conduit |32. A snap acting switchmeans |38 is provided for controlling the operation of the compressormotor |22, and the operating bellows of this snap acting switch means isconnected by a small tube |54 to a thermostat bulb located within a wellin the. T-shaped fitting |34 in like manner as the Well and bulb areembodied in the T-shaped fitting as shown in Fig. 3.

'I'his T-shaped fitting provided with a well or thermostat bulb may beused in connection with new refrigerating equipment or it may beincorporated into old refrigerating equipment merely by sweating the twolegs or ,arms of 'the T-shaped fitting to the outlet of the evaporating5 means and to the return conduit.

While the form of embodiment of the invention 'as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of l0 the claims whichfollow. f

What is claimed is as follows:` ,Y

1. Refrigerating apparatus including liquefying means and evaporatingmeans, conduit means connecting the liquefying means and the evapol5rating means, said conduit means including a multi-legged portionprovided with a well in one of the legs,`said well being provided with ametal wall and being fastened to and sealed to the wall of one of theleg portions for closing said one 20 leg portion, a control means forcontrolling said apparatus, said control means including a thermostatbulb located within said well and in heat exchange relationship throughthe wall of the well with the fluid flowing through the, conduit 25.means, and yielding means within the well for holding said bulb tightlyagainst one of the side walls of the well.

2. Refrigerating apparatus including liquefying means and evaporatingmeans, conduit 30,

means connecting the liquefying means and the evaporating means, saidconduit means including a plural legged tting having one leg c onnectedto the outlet of .the evaporating means and another leg, said fittinghaving a third leg substantially in alignment with one of the otherlegs, a cap member and a Well having its mouth fastened to an aperturein the cap member for closing said third leg, said cap member beingfastened and sealed into the mouth of said third leg, said wellextending into the fitting from the cap member.

3. Re'frigerating apparatus including `liquefy ing means and evaporatingmeans, conduit means connecting the liquefying means and the evaporatingmeans, said conduit means including a plural legged fitting having oneleg connected to the outlet of the evaporating means and another leg,said iitting having another leg substantially in alignment with one ofthe other legs, 50 said another leg being closed by means including awell extending into the leg with which it 1s in alignment, and meansincluding a thermostat bulb in said well for controlling the circulationof refrigerant through the evaporating means, said 55 well extending allthe way through and beyond the fitting, to cause the end of the well toproject into the path of the flow of refrigerant through said one andsaid first mentioned another leg.

DANIEL L. KAUFMAN. 90

